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What This Guide Helps With
Troubleshooting missing CO₂ or SpO₂ data caused by disabled monitoring, loose connections, damaged sensors, contaminated adapters, poor signal, or configuration issues.
Step-by-Step Troubleshooting
1. Ensure Patient Safety First
Do not troubleshoot unreliable CO₂ or SpO₂ monitoring while the ventilator is supporting a patient when either parameter is clinically required.
- Notify respiratory therapy and the clinical team.
- Provide verified independent CO₂ or SpO₂ monitoring.
- Transfer the patient to another ventilator when troubleshooting could interrupt ventilation.
- Confirm that ventilation, oxygenation, and local alarms remain available.
Expected outcome: The patient is safely supported without relying on the affected monitoring function.
Continue Clinical Engineering troubleshooting only when the device can be evaluated safely.
2. Confirm Which Monitoring Function Failed
Determine whether the problem affects:
- CO₂ monitoring only
- SpO₂ monitoring only
- Both CO₂ and SpO₂
- Numerical values only
- The CO₂ waveform or SpO₂ plethysmogram
- Intermittent rather than complete signal loss
Record the exact alarm or message shown on the ventilator.
Expected outcome: The failure is clearly identified before components are disconnected or replaced.
3. Verify the Monitoring Option Is Installed
Confirm that the ventilator is configured with the applicable CO₂ or SpO₂ monitoring hardware and licensed option.
Do not assume every HAMILTON-C6 has both monitoring capabilities installed. Hamilton identifies CO₂ and SpO₂ as optional integrated accessories on applicable configurations.
Expected outcome: The requested monitoring function is supported by the ventilator’s installed configuration.
If the option is not installed, stop troubleshooting and report the configuration limitation.
4. Confirm the Sensor Is Enabled
From the ventilator display, open:
System > Sensors > On/Off
Verify that the appropriate selection is enabled:
- CO₂ sensor
- SpO₂ sensor
The C6 requires CO₂ and SpO₂ monitoring to be individually enabled before their data becomes available.
Expected outcome: The required sensor is enabled and its monitoring fields become available.
If enabling the sensor resolves the issue, verify stable operation and stop.
5. Inspect the External Connection
Trace the affected sensor from the patient end back to the ventilator.
Check for:
- A partially inserted connector
- Bent, recessed, contaminated, or damaged contacts
- A loose adapter connection
- Cable cuts, crushing, excessive bending, or strain
- Fluid intrusion around connectors
- Connection to the wrong accessory port
Disconnect and reconnect the sensor using proper connector alignment. Do not twist or force the connector.
Expected outcome: The sensor and adapter are fully seated with no visible damage.
If reseating restores monitoring, perform a functional verification and stop.
6. Power-Cycle the Monitoring Accessory
When safe and permitted by facility procedure:
- Disconnect the CO₂ or SpO₂ accessory.
- Wait several seconds.
- Reconnect it firmly.
- Allow the ventilator time to recognize and initialize the sensor.
For CO₂, allow any displayed warm-up period to complete before judging performance.
Expected outcome: The ventilator recognizes the accessory and begins displaying valid monitoring information.
7. Check the CO₂ Sensor and Airway Adapter
For a CO₂ complaint:
- Verify that the CO₂ sensor is attached completely to the airway adapter.
- Confirm that the airway adapter is the correct type and size for the application.
- Inspect the adapter windows for moisture, secretions, medication residue, cracks, or clouding.
- Replace a contaminated or damaged disposable adapter.
- Verify that the sensor cable is not pulling against the airway connection.
- Position the assembly according to facility procedure to reduce condensate interference.
The C6 supports external CO₂ sensor and airway-adapter assemblies, including mainstream configurations.
Expected outcome: The adapter is clean, correctly assembled, and capable of passing a stable optical CO₂ signal.
If replacing the adapter restores the capnogram and values, verify operation and stop.
8. Check Sidestream Components, If Equipped
For a sidestream CO₂ configuration:
- Inspect the sampling line for kinks, disconnection, blockage, moisture, or contamination.
- Verify that the sampling line is securely connected at both ends.
- Replace the sampling line or water-trap component with a compatible known-good item when available.
- Check for an occlusion or sampling-related alarm.
Do not attempt to clean or reuse single-use sampling components.
Expected outcome: The sampling path is open, dry, and properly connected.
9. Check the SpO₂ Adapter and Patient Sensor
For an SpO₂ complaint:
- Confirm that the SpO₂ adapter is connected securely to the ventilator.
- Confirm that the patient cable is fully connected to the adapter.
- Inspect the sensor and cable for cuts, stretched conductors, cracked housings, or damaged contacts.
- Verify that the sensor technology is compatible with the installed C6 SpO₂ system.
- Confirm that the sensor type is appropriate for the test being performed.
Hamilton C6 configurations may use an external SpO₂ adapter containing the pulse-oximetry hardware, with a compatible patient sensor connected to it.
Expected outcome: All SpO₂ components are compatible, undamaged, and fully connected.
10. Rule Out a Poor SpO₂ Signal
When performing an operational check:
- Apply the sensor correctly to a suitable test subject or approved simulator.
- Remove nail coverings or other optical obstructions when applicable.
- Minimize motion.
- Verify that the sensor is not excessively tight or loose.
- Check for a visible plethysmogram and pulse rate.
- Compare the displayed pulse rate with an independent reference.
A numerical SpO₂ value without a stable plethysmogram may indicate poor signal quality rather than ventilator failure.
Expected outcome: A stable plethysmogram, pulse rate, and SpO₂ value appear.
11. Substitute Known-Good External Components
Use compatible, verified components to isolate the failure.
For CO₂, substitute one component at a time:
- Airway adapter
- Sampling line, if applicable
- CO₂ sensor
- Sensor cable, when separable
For SpO₂, substitute one component at a time:
- Patient sensor
- Patient cable
- SpO₂ adapter
Do not substitute incompatible brands or technologies merely because the connectors appear similar.
Expected outcome: The failed external component is identified without replacing multiple parts unnecessarily.
If a known-good accessory resolves the issue, replace the defective component and stop.
12. Review Alarms and Perform Available Checks
Review the alarm history and displayed messages for indications such as:
- Sensor disconnected
- Sensor defective
- Adapter check required
- CO₂ calibration or zeroing required
- Sampling line blocked
- SpO₂ sensor off
- Poor signal quality
- Communication or hardware error
Perform only the user-accessible calibration, zeroing, or test functions authorized by the operator documentation and facility procedure. Do not perform internal adjustments.
Expected outcome: Required external calibration or sensor checks complete successfully.
13. Restart the Ventilator Off Patient
After the patient has been safely transferred and configuration information has been recorded:
- Shut down the ventilator normally.
- Disconnect and inspect the monitoring accessory.
- Restart the ventilator.
- Reconnect the accessory.
- Enable the sensor if necessary.
- Test the system with a known-good accessory or approved simulator.
Expected outcome: The ventilator recognizes the monitoring accessory after a controlled restart.
If the accessory still is not recognized, proceed to escalation.
If the Problem Persists
If compatible known-good sensors, adapters, cables, sampling components, settings, and external connections have been verified, common external causes have been ruled out.
The problem may involve:
- The monitoring communication interface
- The accessory input connector
- The installed option hardware
- Internal power to the monitoring accessory
- Software or configuration corruption
- An internal communication-board failure
The ventilator should be:
- Removed from service
- Labeled Out of Service
- Sent for qualified repair or bench evaluation
- Evaluated using the applicable Hamilton service documentation and approved test equipment
Do not open the ventilator or replace internal assemblies during routine floor troubleshooting. Knowing when to stop is proper troubleshooting.
Clinical Use Tip
Do not depend on missing or intermittent integrated CO₂ or SpO₂ values during patient care. Provide independent monitoring or move the patient to another verified ventilator before disconnecting sensors, restarting the C6, or performing tests that could affect therapy.
Work Order Documentation (CCR Method)
CCR = Complaint, Cause, Resolution
Complaint
What was reported by the clinical staff.
Example:
"Respiratory therapy reported that the HAMILTON-C6 displayed no CO₂ waveform or SpO₂ value after the monitoring accessory was connected."
Cause
What was observed during troubleshooting.
Example:
"Inspection found a damaged SpO₂ adapter cable that failed with movement, while the ventilator operated normally with a compatible known-good adapter and sensor."
Resolution
What action was taken.
Example:
"Replaced the defective SpO₂ adapter, enabled SpO₂ monitoring, verified a stable plethysmogram and value, and returned the ventilator to service."
Helpful Details to Include (If Known)
- CO₂, SpO₂, or both affected
- Exact alarm or message
- Sensor enabled in configuration
- Installed monitoring option confirmed
- Connector and cable condition
- CO₂ adapter condition
- Sampling-line condition
- SpO₂ plethysmogram behavior
- Known-good components tested
- Recognition after restart
- Calibration or zeroing result
- Final device status
Final Thought
Patient monitoring problems should be approached by protecting the patient first, identifying the exact failed function, and checking configuration, connections, accessories, and signal quality before suspecting internal failure. Clear CCR documentation supports safe repair decisions and prevents repeated troubleshooting.
That is successful troubleshooting.